CSS and Bootstrap overview and implementation examples

About CSS

CSS (Cascading Style Sheets) is a style sheet language used to specify the style and layout of documents created in markup languages such as HTML and XML, and is used to decorate the appearance of web pages, specifying font color and size, background color, images, It can specify font color and size, background color, images, margins, layout, and so on.

The basic functions and usage of CSS are described below.

• How to apply styles:
  • Inline style: CSS properties are directly specified in the style attribute of an HTML element.
  • Internal style sheet: Embed CSS code within an HTML file using <style> tags.
  • External Style Sheet: Create a separate CSS file and reference it in the HTML file using <link> tags.
• Selectors: CSS uses selectors to select elements. Selectors identify elements based on HTML elements, classes, IDs, and other attributes. For example, an h1 selector would select the HTML <h1> element.
• Properties and Values: CSS uses a combination of properties and values to specify the style to be applied to an element. For example, color: red; specifies that the text color should be red.
• Cascading and Inheritance: Cascading is a method of determining precedence when multiple styles are applied to the same element. Inheritance is a mechanism whereby the style of a parent element is applied to its children.
• Classes and IDs: Classes and IDs are used to apply a specific style to an element. A class is used to apply the same style to multiple elements, while an ID is applied to a unique element.
• Box Model: The box model is a concept used to control how an element is laid out. An element is composed of four elements: content, padding, borders, and margins.

While these are the basic features of CSS, CSS is a very flexible language and there are many different properties and techniques to achieve different styles and layouts. In addition, new features and specifications are added to CSS on a regular basis, so it is important to refer to the latest documentation and resources.

About Bootstrap

Bootstrap is a framework for building responsive websites and web applications using HTML, CSS, and JavaScript.

Bootstrap has the following features

• Responsive design: Bootstrap offers responsive designs that automatically adapt to different screen sizes and devices. These can be done using a grid system, such as using a grid system to flexibly arrange content.
• Grid System: Bootstrap offers a 12-column grid system. This allows for flexible design of web page layouts, placing content in columns and automatically adjusting the layout for different screen sizes.
• Components: Bootstrap provides many pre-styled components such as buttons, navigation bars, forms, modals, and cards. Using these components, you can easily create elements with a consistent look and functionality.
• Customizable: Bootstrap allows you to customize the look and functionality of the framework using CSS variables and Sass (Syntactically Awesome Style Sheets). These make it possible to change the theme or use only certain components as needed.
• Browser Compatibility: Bootstrap is compatible with all major browsers (Chrome, Firefox, Safari, Edge, etc.). Furthermore, it is designed to display properly on a variety of devices, including mobile devices and tablets.

With the above features, Bootstrap can be used to efficiently build websites and applications. Next, we will discuss some examples of Bootstrap applications.

Examples of Bootstrap Applications

Bootstrap is widely used in the development of various websites and web applications, and some examples of Bootstrap applications are described below.

• Responsive websites: Bootstrap’s grid system and responsive components make it possible to build websites for different devices and screen sizes. These can combine components such as navigation bars, buttons, forms, and carousels to create websites with a consistent look and functionality.
• Dashboards and administration screens: Bootstrap can also be a useful tool for creating administration screens and dashboards. It has pre-styled tables, charts, cards, modals, and other components that allow you to build interfaces for displaying and manipulating data.
• Multi-device applications: Bootstrap is also used for front-end development of mobile and tablet applications. Responsive design and mobile-friendly components can be used to create applications that work on different devices.
  Prototyping: Bootstrap is also useful for prototyping ideas and concepts. You can quickly prototype and test designs and usability using pre-prepared styles and components.
• Theme Development: Because Bootstrap is a customizable framework, it is also possible to create your own themes and design systems. Using variables and Sass, you can customize Bootstrap’s styles and components to achieve a look and feel that matches your brand and design guidelines.

Finally, we will discuss specific implementations of these use cases.

Example of Bootstrap responsive website implementation

Below is a basic code example for implementing a responsive website using Bootstrap.

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/5.0.0/css/bootstrap.min.css">
<title>Responsive Website</title>
</head>
<body>
<nav class="navbar navbar-expand-lg navbar-dark bg-dark">
<div class="container">
<a class="navbar-brand" href="#">My Website</a>
<button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarNav">
<ul class="navbar-nav ms-auto">
<li class="nav-item">
<a class="nav-link" href="#">Home</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">About</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Services</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Contact</a>
</li>
</ul>
</div>
</div>
</nav>

<header class="jumbotron jumbotron-fluid">
<div class="container">
<h1 class="display-4">Welcome to My Website</h1>
<p class="lead">Lorem ipsum dolor sit amet, consectetur adipiscing elit.</p>
</div>
</header>

<div class="container">
<div class="row">
<div class="col-md-6">
<h2>About</h2>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer gravida nulla ut purus pulvinar.</p>
</div>
<div class="col-md-6">
<h2>Services</h2>
<ul>
<li>Web Design</li>
<li>Responsive Development</li>
<li>Mobile App Development</li>
</ul>
</div>
</div>
</div>

<footer class="bg-dark text-white text-center py-4">
<p>&copy; 2023 My Website. All rights reserved.</p>
</footer>

<script src="https://stackpath.bootstrapcdn.com/bootstrap/5.0.0/js/bootstrap.bundle.min.js"></script>
</body>
</html>

In this example, the CSS and JavaScript files are loaded using Bootstrap’s Content Delivery Network (CDN). The structure of a typical website is shown here, including the navigation bar, header, content, and footer.

Bootstrap classes (e.g., navbar, container, row, col-md-6, etc.) are used to achieve responsive layout and styling, and content is arranged in two columns using a grid system to display properly at different screen sizes.

Example implementation of a dashboard or admin screen using bootstrap

Below is a basic code example for implementing a dashboard or admin screen using Bootstrap.

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/5.0.0/css/bootstrap.min.css">
<title>Admin Dashboard</title>
</head>
<body>
<nav class="navbar navbar-expand-lg navbar-dark bg-dark">
<div class="container">
<a class="navbar-brand" href="#">Admin Dashboard</a>
<button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarNav">
<ul class="navbar-nav ms-auto">
<li class="nav-item">
<a class="nav-link" href="#">Dashboard</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Users</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Products</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Settings</a>
</li>
</ul>
</div>
</div>
</nav>

<div class="container-fluid">
<div class="row">
<div class="col-lg-2 bg-dark text-white">
<ul class="nav flex-column">
<li class="nav-item">
<a class="nav-link" href="#">Dashboard</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Users</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Products</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Settings</a>
</li>
</ul>
</div>
<div class="col-lg-10">
<div class="container mt-4">
<h1>Welcome to the Admin Dashboard</h1>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer gravida nulla ut purus pulvinar, a suscipit felis blandit.</p>
</div>
</div>
</div>
</div>

<script src="https://stackpath.bootstrapcdn.com/bootstrap/5.0.0/js/bootstrap.bundle.min.js"></script>
</body>
</html>

In this example, the CSS and JavaScript files are loaded using Bootstrap’s CDN. The structure of a typical admin page is shown here, including the navigation bar, sidebar menu, and main content.

The sidebar is styled using Bootstrap’s bg-dark and text-white classes to display the admin menu items, and the main content section uses Bootstrap’s grid system to place content.

Multi-device applications

Below is a basic code example for implementing a multi-device application using Bootstrap.

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/5.0.0/css/bootstrap.min.css">
<title>Multi-Device App</title>
</head>
<body>
<header class="navbar navbar-dark bg-dark">
<div class="container">
<a class="navbar-brand" href="#">App Logo</a>
<button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarNav">
<ul class="navbar-nav ms-auto">
<li class="nav-item">
<a class="nav-link" href="#">Home</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Features</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Pricing</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Contact</a>
</li>
</ul>
</div>
</div>
</header>

<div class="container">
<div class="row">
<div class="col-lg-6">
<h1>Welcome to our App</h1>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer gravida nulla ut purus pulvinar, a suscipit felis blandit.</p>
<a href="#" class="btn btn-primary">Get Started</a>
</div>
<div class="col-lg-6">
<img src="image.png" alt="App Screenshot" class="img-fluid">
</div>
</div>
</div>

<section class="container mt-4">
<div class="row">
<div class="col-md-4">
<h2>Feature 1</h2>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer gravida nulla ut purus pulvinar, a suscipit felis blandit.</p>
</div>
<div class="col-md-4">
<h2>Feature 2</h2>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer gravida nulla ut purus pulvinar, a suscipit felis blandit.</p>
</div>
<div class="col-md-4">
<h2>Feature 3</h2>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer gravida nulla ut purus pulvinar, a suscipit felis blandit.</p>
</div>
</div>
</section>

<footer class="bg-dark text-white text-center py-4">
<p>&copy; 2023 Our App. All rights reserved.</p>
</footer>

<script src="https://stackpath.bootstrapcdn.com/bootstrap/5.0.0/js/bootstrap.bundle.min.js"></script>
</body>
</html>

In this example, the CSS and JavaScript files are loaded using Bootstrap’s CDN. The structure of the multi-device application is shown here, including the header, content section, and footer.

A responsive navigation bar is shown, properly adjusted for different screen sizes, and the content section uses Bootstrap’s grid system to arrange multiple featured sections side by side.

Example of prototyping implementation using bootstrap

Below is a basic code example for implementing prototyping using Bootstrap. This will serve as a prototype example of a user registration form.

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/5.0.0/css/bootstrap.min.css">
<title>User Registration Prototype</title>
</head>
<body>
<div class="container">
<h1>User Registration</h1>
<form>
<div class="mb-3">
<label for="name" class="form-label">Name</label>
<input type="text" class="form-control" id="name" placeholder="Enter your name">
</div>
<div class="mb-3">
<label for="email" class="form-label">Email address</label>
<input type="email" class="form-control" id="email" placeholder="Enter your email">
</div>
<div class="mb-3">
<label for="password" class="form-label">Password</label>
<input type="password" class="form-control" id="password" placeholder="Enter your password">
</div>
<div class="mb-3">
<label for="confirm-password" class="form-label">Confirm Password</label>
<input type="password" class="form-control" id="confirm-password" placeholder="Confirm your password">
</div>
<button type="submit" class="btn btn-primary">Register</button>
</form>
</div>

<script src="https://stackpath.bootstrapcdn.com/bootstrap/5.0.0/js/bootstrap.bundle.min.js"></script>
</body>
</html>

In this example, the CSS and JavaScript files are loaded using Bootstrap’s CDN. Here, the name, email address, password, and password confirmation fields are displayed as a prototype for a user registration form. Furthermore, Bootstrap classes (e.g. container, form-control, btn btn-primary, etc.) are used to achieve the styling and layout of the form elements.

Example implementation of theme development using bootstrap

Implementation examples for theme development using Bootstrap vary depending on the individual theme and design, but the following are general steps and basic code examples.

1. Project Setup and Bootstrap Deployment:.
   • Download Bootstrap files and CDN to the root of the project and place the files in the project.
   • Load the Bootstrap CSS file within the <head> section of the HTML file.

<link rel="stylesheet" href="path/to/bootstrap.css">

2.Adding custom styles:.

• • Create a custom CSS file to override Bootstrap’s default styles.
  • Load the custom CSS file within a section of the HTML file.

<link rel="stylesheet" href="path/to/custom.css">

3. Create Layout:.
   • Create common layout elements such as sidebars, headers, footers, etc.
   • Create responsive layouts using Bootstrap’s grid system and components.

<div class="container">
<header>
<!-- Header Content -->
</header>

<div class="row">
<div class="col-md-3">
<aside>
<!-- Sidebar Content -->
</aside>
</div>

<div class="col-md-9">
<main>
<!-- Main Content Content -->
</main>
</div>
</div>

<footer>
<!-- Footer Content -->
</footer>
</div>

4. Creating Custom Components:
   • Create custom components based on Bootstrap components.
   • Customize styles and behavior as needed.

<div class="alert alert-primary" role="alert">
This is a custom alert!
</div>

<button class="btn btn-primary">Custom Button</button>

5. Page content creation:
   • Create content for each page and use the styles and components of the theme you wish to apply.

<div class="container">
<h1>Page Title</h1>

<div class="row">
<div class="col-md-6">
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit.</p>
</div>
<div class="col-md-6">
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit.</p>
</div>
</div>
</div>

Reference Information and Reference Books

For more information on CSS and Bootstrap, See also “Web Design with CSS“.

A good reference book on CSS is Html and css: Design and build websites with html and Css

“CSS in Depth“

“CSS: The Definitive Guide“

For Bootstrap, there is Learning Web Development with Bootstrap

“Make Bootstrap Themes”